MGM buffet was decent. Tried their bfast and lunch buffet as I had 2 free buffets that came with my stay.
Anyway, the buffet for buffets is not exactly cheap imo. Isn't it like 50usd for a 1 day pass? How many buffets can you eat in a 24hour span? 3 at most? There's SO much good food in Vegas! Some Michelin starred restaurants also go for like 30% discounts at the tix4tonight booths. Buffet @ Flamingo was 70% off once. Would definitely recommend you to try 1 of those Michelin starred restaurants. Much cheaper over in Vegas as compared to S'pore. Those celebrity chef restaurants in MBS over here are hell exp.
Joel Robuchon @ MGM, a 3 Michelin star restaurant have a 3 course set for 50usd. not sure if they still have it now. that was about 1month ago.
You can also hunt for happy hour specials, some places have happy hour that starts from like 11pm, up to 6am. Like steak and hashbrown(their hashbrown is like rosti) for 8usd?
I went into Wynn to take a look at the spread. Their crab legs were huge. Spread looked really good, better than MGM for sure. In fact there was quite a queue when I was there at 6+pm. Their dinner buffet usually starts at 4.30pm so do check the exact timings.
p.s you can check out tripadvisor, search "las vegas forums". I got ALOT of help from there whilst planning my trip. search for buffet of buffets, there was a thread on it and quite a lot people not recommending ppl to buy it lol. though i have not tried any of the hotels in the buffet of buffets.